Tantalum capacitors of the solid-electrolyte type have been a major contributor to the miniaturization of electronic circuitry. They also have the advantage of operating over a wide temperature range and have good shelf life, long service life and are useful in extreme environments.
Typically such capacitors have been manufactured by compressing tantalum powder into a pellet, and sintering the pellet to form a porous body. The porous body is then anodized in a suitable electrolyte to form a continuous dielectric oxide film on the sintered body. The pores are filled with an electrolyte and a lead wire is attached to form the capacitor.
As the requirements for smaller and smaller anodes come out of the electronics industry with the increased miniaturization of electronics, this presents new challenges to the tantalum anode industry. With smaller and smaller anodes, the lack of high frequency performance of the anode becomes a bigger and bigger problem. Furthermore, the smaller the anode, the greater difficulty manufacturers are confronted with in automated handling of the anodes, e.g. in attaching a lead wire. Certain manipulation is required to attach such a wire, and it becomes difficult to handle the miniaturized anodes in a manner sufficient to cost effectively attach such a wire.
Accordingly, what is needed in the art is an improved method for making smaller electrodes, and electrodes themselves which overcome such difficulties.